thanks for the reply, yes it was a while ago.
I just found the problem I was having, I had to turn sendchunked to false. now I have no problems, I was already closing the response objects when using them. I have keepalive true, and unsafeconnectionsharing (not exact name) true.
me->server: POST request
me->server: post body
server->me: 200 OK
server->me: 400 Bad Request
it was issuing two responses for 1 request, dont know whats up with that. maybe an IIS bug??
it was happenning on random things too, like the 4th request in the "keepalive" connection, or the 6th. but always after a binary post payload.
in any case, thanks for your response